Tektronix 556 and 565 Dual-beam Oscilloscopes

“Oh my gosh look at that, and they boast two channels — hilarious! My old ‘scope used to do four or eight hands down!” It’s a common response from people rst confronted with the Tektronix Types 556 and 565 cathode-ray tube (CRT) oscilloscopes, two of the largest, heaviest and most expensive instruments ever to serve electronicists in their labs if only for heating. These Goliaths are often regarded as the pinnacle of the tubed oscilloscopes from market leader Tektronix, although they contain more than a handful of semiconductors and there’s at least one Tek ‘scope that’s even heavier.